Twelve hundred and fifty individuals of were sampled from the coast of Zhaitang Island, Qingdao (using stow nets, in 2015), and their sex ratio, secondary sexual characteristics, gonadosomatic index (GSI), gonad maturity levels, egg diameter, and number of embryos in the pouch were examined. The results showed that the abundance of females was higher than that of males in the area, with a total sex ratio of 1.75:1, deviating significantly from a 1:1 sex ratio, and the sample comprised 63.28% females, 36.24% males, and 0.48% underage individuals. The gonadosomatic index (GSI) range in males in the breeding population was maintained at a relatively low level of 0.01% to 4.85%, and the GSI in females ranged from 0.05% to 128.99%, and was significantly different from that of the males (S. schlegeli quickly matured from March to May. After spermiation, some sperm cells remained in the testis of male , showing that multiple spermiation events may occur. In the female breeding groups, different phases of eggs appeared in the stage Ⅲ-VI ovary, and the egg-diameter distribution had two peaks, indicating a multiple-batch spawning pattern. The number of mature eggs in the stage V ovary was in accordance with the number of eggs in the paternal brood bags, and the embryos in the paternal brood bags were at the same stage, suggesting monogamous mating, or polygamy whereby males mated with multiple females on the same day. Evidence for the mating patterns of on the coast of Zhaitang Island needs to be shown by behavioral observation and microsatellite analysis.